Panoramic
radiography as well as periapical radiography are routinely used in dental
practice. Because of some limitations and providing low detailed, unsufficient
information reveal some difficulties in assessment of vital structures. By the
increase of dental implant procedures and widespread acceptance of CBCT
applications showed that accurate diagnosis can only be achieved by choosing
the appropriate imaging modality. CBCT allows accurate and high resolution
images to assess anatomical structures including incidental findings. Although,
incidental findings mostly asymptomatic and requiring any treatment but some
variations or pathologies which incidentally found in radiographic examination
may be a cause for an alteration of treatment plans or
priority. Aim of this case report is to present an unusual situation
which was incidentally found in CBCT assessment before dental implant procedure.

Since the first
insertion of dental implant in 1965 by Branemark[1]
and with the significant development of implant technology, dental implants
have become widely used in dentistry to replace missing teeth.Therefore,
evaluation of alveolar structure plays an important role to achieve success in
dental implant practice. This procedure was routinely made by a comprehensive clinicaland
radiographic examination

Conventional radiographic techniques
such as periapical and panoramic radiology are used commonly in dental
practice. Although they have some limitations but they have also provide
significant information about anatomical structures. They provide
two-dimensioned images of three dimensioned structures. The images obtained by
using these modalities have some disadvantages such as magnification,
distorsion or superimpositions. Due to poor quality images of anatomical
structures, practitioners need to obtain more sufficient and accurate information.
Therefore, three-dimensional sectional imaging modalities have been gained
popularity in evaluation of anatomical structures, their variations and
pathologies. With widespread acceptance of CBCT applications in dentistry, CBCT
scans provide more accurate information on anatomic structures and
characteristics of pathologies rather than the conventional techniques. It also
provides high-resolution cross-sectional images and diagnostic reliability at lower
costs and radiation doses[2-7].

CBCT images
allow to obtain more accurate information not only from structural knowledge of
anatomy but also incidental findings. Incidental findings are defined as
results that are outside the original purpose for which a procedure was
conducted. An incidental finding would be an anatomic variation or a pathology.
They are mostly asymptomatic and requiring any treatment. But in a presence of an incidentally found anatomical variation or pathologies may be a
reason for an alteration of treatment plans or priority. Increasing the
knowledge of dentomaxillofacial anatomy and a better understanding of
incidental findings will lead practitioners to avoid misinterpretations and
misdiagnosis [6,8].

Antroliths
defined as calcified masses within the paranasal sinuses.The origin of the
calcified deposits may be extrinsic or intrinsic. Most of them are small and asymptomatic.Unless they reach larger sizes
and present sinusitis findings such as pain and discharge, intervention is not
required. Due to their asymptomatic nature when they were small, and
because of the limitations of imaging technique, they are rarely detect by
conventional radiographic modalities but easilydiscovered in CBCT images as an
incidental finding [9].

Anatomical variations is one of the
incidental findings.Canalis sinuosus is a bony canal where the
anterior superior alveolar nerve passes through, contains arteries and veins. Especially in presence of accessory canals deriving
from canalis sinuosus reveal some difficulties to practitioners in anterior
maxillary surgery procedures. Accurate diagnosis should be made of this
anatomical variant to avoid complications.Hence, morecomprehensive radiographic
evaluation should be performed by CBCT.But due to superimpositions in panoramic
radiography which routinely performed in dentistry, it is not always possible to
obtain accurate diagnosis[10,11].

The aim of this case presentation is to report some incidental findings
which were not observed in panoramic radiographs but incidentally found on CBCT
images.

2.Case
Report

A 44-year-old male patient referred to the Department of Dentomaxillofacial
Radiology, Gulhane
Faculty of Dentistry, Ankara, Turkey with a complaint
of maxillary and mandibular partial edentulism. A comprehensive examination
started after we obtained an informed consent from the patient. He had no history of any systemic disease and did not
use any medication. It was learned that the patients wanted to have an implant
rehabilitation. First of all, it was performed a panoramic radiograph to assess
whole dentomaxillofacial structures. On panoramic evaluation, broad periodontal
disease with severe bone resorption and a calcified mass in the right maxillary
sinus were observed (Figure 1). In order to
determine the appropriate surgical approach and to obtain more detailed
information, it was decided for an examination by 3D Accuitomo 170
(3D Accuitomo; J Morita Mfg. Corp., Kyoto, Japan). On CBCT assessment it was
seen bilateral antroliths which was not noticed on panoramic
radiograph. On coronal view of CBCT it was seen partial opacification in the
left and mucosal thickening in the right maxillary sinus. It was also seen
irregular, well defined calcified masses in both maxillary sinuses (Figure 2). Sagittal and axial views were seen on (Figures 3,4). On evaluation of anterior maxilla, it
was also seen a canalissinuosus which runs from the floor of nasal fossa to
alveolar ridge (Figure 5). Therefore, the oral
and maxillofacial surgeon was informed about the findings and a comprehensive and
detailed dental implant treatment planning was performed in order to avoid
neurovascular bundle damage.

3.Discussion

Various surgical
procedures have been performed in dentomaxillofacial area by oral surgeons. But
dental implant placement procedures is no longer performed only by oral
surgeons; practitioners are also increasingly providing difficult surgical
implant performances. To avoid unexpected complications and to increase the
success rate, accurate radiographic evaluationis a crucial aspect. Furthermore,
clinicians should increase their knowledge of anatomical structures.

Digital or
conventional a number of imaging modalities have been used to
evaluate bone quality, quantity, and location of anatomic structures. Although,
panoramic radiography is the most commonly used and
relied imaging modality by clinicians but it should be understood the inherent
fundamental limitations such as superimpositions, magnifications, distortions
and low image quality[11,12].Although
their relatively low cost and widespread availability, but because of the
difficulty of interpret anatomical structures on two-dimentional plane, made necessary to be developed three-dimentional
imaging techniques.To overcome of these disadvantages
and to obtain more accurate images of anatomical structures, a new era opened
by the invention of CBCT.

CBCT technology allows clinicians precious information not only about
anatomical structures, but also about the pathologies or findings outside the
primary area of interest. The findings which were unexpectedly discovered
outside the primary area of interest are defined as incidental findings. Owing
to CBCT, it became difficult to misdiagnosis of normal anatomic variants,
developmental anomalies or artifacts as pathology [6,7].

Antroliths occur
by the precipitation of calcium phosphate, calcium carbonate and magnesium
salts[13,14].They are rare and are commonly
discovered by conventional radiographic
modalities only if they reach larger size. And also, they usually don't cause any symptoms unless they're
large. Hence asymptomatic smaller sized antroliths have been overlooked
and there is only a few studies about their prevalence in population in the
literature. Although the study of Nalcaci and
Gorgun[15] were performed by using panoramic
radiographs, they reported that incidence of this condition was 5.4%. Nass
Duce et al[16] found three cases in 1957
patients’ CT scans. Altindag et al.[7]was reported
as 2.33%, and one another report by Khadija et al.reported as 3%[17]. Except the study which were reported only three antrolith
cases by Nass Duce et al.[16], literature shows
anincreased female gender predisposition [7,15,17].

Accessory canals
of canalis sinuosus are rare condition which located in the anterior maxilla.
This anatomic structure and its variation are not well known and ignored by
clinicians. Due to it contains anterior superior alveolar nerve as
well as vein and arteries, exact diagnosis will provide surgeons to avoid nerve
damage, unexpected bleeding, hemorrhage and complications. In addition to these
complications, replacing an implant contacted with the neurovascular bundle will
be led to non-integration [11].

There are only a
few articles which were available in literature. According to Pubmed
database,”canalis sinuosus” term reveals only 16 results. Only 6 of 16 results
were case reports.According to the publishing dates, by the increase of dental
implant procedures and widespread acceptance of CBCT applications showed that
this phenomenon has been gained its popularity in the last two decades.

There are several reports [18,19]which
emhasized that canalis sinuosus were rare but Wanzeler et al.[20] reported the frequency of this structure as
87.5% in 100 CBCT scans. These differences can be explained by the size of the
sample, and the radiological
interpretation that was performed by different radiologists. Aim of this case report
is to pay attention to a rare variation of canalis sinuosus.

4.Conclusion

The anatomical
variations or pathologies could be missed frequently in routine panoramic
radiographic examination. Increasing
the knowledge about anatomical structures and their variations will provide the
clinicians to avoid complications during surgery procedures. The
limitations of conventional imaging modalities should be known and especially
in suspected cases, multiplanar imaging modalities should not be ignored as an
alternative approach for accurate information. Hence, comprehensive and detailed preoperative radiologic
evaluation should be applied by using appropriate radiologic technique.

Figure 1:A
panoramic radiograph was obtained from the patient who was referred for implant
rehabilitation. Although the panoramic radiograph reveals sufficient
information about vertical height it has also some limitations to evaluate bone
quality. It was also detected a suspected radioopacity in the right
maxillary sinus(arrow).

Figure 2:Coronal
slices show mucosal thickening in the right, partial opacification in the left
maxillary sinus. In addition it is also seen bilateral antroliths.

Figure 3:Sagittal
view of CBCT scan. Calcified masses are
in the both maxillary sinuses.

Figure 4:Axial
view of bilateral calcifications in maxillary sinus.

Figure 5: Coronal slices show
branch of canalis sinuosus. It is a branch of anterior superior alveolar nerve.
Presence of this variation will be forced clinician to alter implant planning.
This bony canal where the anterior superior alveolar nerve passes through,
contains arteries and veins.

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